[Hafnium] Questions about Hafnium as S-EL2

Hello,

I'm Junho Choi in Samsung S.LSI and I've been working on virtualization solution.

I have some questions about Hafnium for Secure EL2 extension.

(1) Why do you consider VHE as default option? (I saw it in arch_mm_init)

According to Hafnium init sequence, has_vhe_support always returns true as long as ARM cores have support for VHE.

Is there any requirements that Hafnium should support VHE?

(2) TF-A's SPMD has only forwarded svc_on_finish and svc_off of PSCI.

Why doesn't SPMD forward other commands such as CPU_SUSPEND?

In case of the CPU_SUSPEND, secure EL2 or SP may need to know when physcial CPU turns off.

(3) Why do you set HCR_EL2.VI and VF to handle virtual interrupt?

I think we have an another method to use List registers (ICH_LRn_EL2) to inject virtual interrup to guest (SP).

I'm not sure whether asking you is proper or not.

If you're not the right person, please forward this mail to the right person.

Thanks!

Best Regards,

Junho Choi

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